Separation of materials of different specific gravities



NOV. 12, 1940. WALKER 2,220,925

SEPARATION OF MATERIALS OF DIFFERENT SPECIFIC GRAvITIEs Filed Aug. 16; 1958 4 Sheets-Sheet l IIII'IIIIIIII Marcus fil/mlker, G ul W A TTORNEYS.

NOV. 12, 1940. WALKER 2,220,925

SEPARATION OF MATERIALS OF DIFFERENT SPECIFIC GRAVITIES Filed Aug. 16, 1938 4 Sheets-sheaf. 2

1 NESSES; Z5 ZZZ IVNVEINTOR; W 20 Marcus :6? TELL/c122 I BY m M J v ATTORNEYS.

Nov. 12, 1940.

M. A. WALKER 2,220,925 SEPARATION OF MATERIALS OF DIFFERENT SPECIFIC GBAVITIES Filed Aug. 16, 1938 4 Sheets-Sheet 3 \wtl/ FZGJL/t A; b Q/ iii i 1M i INVENTOR- l Zfarcus 26? Walker lax WW A TTORNEYS.

Patented Nov. 12, 1940 urn-: STATES iATEN'l OFFICE 2.220.925 SEPARATION or MATERIAIB or nmrsann'r SPECIFIC enevrrms Marcus A. Walker, lScranton, Pa, assignor to himself and Provident Trust Company of Philadelphia, Philadelphia, Pa., Pennsrlvania, as trustees a corporation of under the will of 1 Thomas M. Chance, deceased Application August 16, 1938, Serial No. 225,100

comma 5 while the heavier material sinks to the bottom.

Such methods are used especially for separating coal from heavier mineral matter, usually with a mixture of sand and water as a liquid separation medium. The sand being more or less uniformly distributed in the water, by agitation, in a suitable vessel or hopper, the mingled broken coal and refuse material are run in at the top. The coal, being lighter thanv the sand-and-water mixture, floats at its surface, and is continually withdrawn from an outlet at the top of the vessel. The heavier refuse sinks and accumulates in the bottom of the vessel, whence it is periodically withdrawn through a suitably controlled discharge.

In the operation of such a system, the larger particles of refuse are very successfully separated and discharged; but it is found, especially in treating materials having a wide diversity in particle size, that there may be improvement. For 5 reasons which I shall explain hereinafter, these smaller. particles of refuse sometimes tend to remain behind in the apparatus when the discharge is opened, instead of passing out along with the larger particles. As this occurs at every discharge, the fine particles accumulate and work upward in the sand and water mixture, thus altering the characteristics of the separation-medium. The small particles of refuse also mingle with and contaminate the coal particularly where. the smaller sizes of coalare being cleaned.

I aim to improve the operation of such a system and to assure substantially complete and uniform separation of all particles of refuse or heavy material from the lighter material or coal,

particularly where substantial differences in particle size prevail. I have hereinafter explained my invention in connection'withone type and form of separating apparatus now in commercial use for separating refuse from coal; but it will be understood that this apparatus and use are only illustrative, and that the invention can be. carried out in connectioniwith other separating apparatus, and by means different from those illustrated and hereinafter described. Various features and advantages of the invention (besides that already referred to) will appear from the following description of particular species or forms of embodiment, and-from the drawings.

In the drawings, Fig. I is a side view of a separating apparatus adapted for the practice of my sand (and water) invention/certain parts being shown in vertical mid-section. I

Fig. Ii is a similar view at right angles to Fig. I, also with parts in vertical section. Fig. 111 is a fragmentary view (mainly sec- 5 tional) on a larger scale, illustrating a structural detail.

Fig. IV is a side view of a separating apparatus illustrating a different species or form of embodiment of my invention. 10

Fig. V. is a similar view, illustrating still another form.

Fig. V1 is a fragmentary side view corresponding to Fig. IV, but illustrating yet another. form of embodiment of the invention. 15

Figs. I and 11 show a separating. apparatus comprising a conical hopper-like vessel l0 containing the liquid separating medium M, of sand .and water, and equippedtwith a revolving paddle agitator il, driven from any suitable source of 20 power through reduction gearing l2. The mingled coal and refuse is supplied by a gravity chute i3 terminating, as shown, just above the surface of theliquid medium M. The lumps or particles of coal C float at the top of the liquid medium M, 25 I and are withdrawn continually at an overflow' outlet or weir l4,--as sho on to a screen l5. Any sand (and water) passing off at the outlet N may be separated from the coal C and (ultimately) returned to the vessel III, as through a' pipe 56 connected to, a lateral extension ll of the vessel in at its top. The refuse materials S sink in the medium M to the bottom of the vessel Land into its discharge conduit M, to a refuse or batch chamber 20, whichmay be of 35 substantial capacity. For discharging the heavy separated matter or refuse, there is'a gate or shut-off valve 2| in the conduit l8. just above the refuse chamber, 20, and just beneath the chamber 20 there is a gate-or discharge valve 22. 40 Below this valve 22 there may be a delivery conduit or chute 23 for 'the' discharged refuse. Any

passing off with. the separated refuse materials S discharged through the gate valves 2|, 22 maybe-separated therefrom and 45 (ultimately) returned to the vessel l0 as through the pipe i6 aforementioned. Valve-controlled water supply pipes 24, 24 are shown connected to the conduit l8, just above the valve 2i, and through these water may be continually supplied to assist in maintaining fluidity of the separating medium M. There is a water supply pipe connection 25 (Fig. 11) to the upper portion of thechamber 20, controlled by a valve 26. There is also shown a pipe or conduit 21 extend- 55 lug upward from the chamber 20 to an open air vent at 28, which may serve to vent the chamber 20 of air when water is being run into it from pipe 25. In the apparatus as heretofore used, the pipe 21 terminates at the vent 28, which is placed high enough above the liquid level in the vessel It to prevent any considerable upsurge-of water in said pipe. The downward extension of the pipe 21 beyond the air vent 28, as here shown, will be explained hereinafter.

As thus far described, the apparatus is well known in the art. In its operation, coal and accompanying refuse are continually run in at the chute l3, and are continuously separated. The l6 gate valve .2! is kept closed until it is desired to discharge the separated refuse that has accumulated in the vessel It and in conduit it, above said valve. The valve 22 being also closed, and the chamber 20 full of water (supplied from the pipe 25), the valve 2i is opened, allowing the refuse material S abovethis valve to descend by gravity into the chamber 2|, as shown in Figs. I and H.

The descent of this heavy refuse into the water filled chamber 20 necessarily displaces a corresponding amount of water. Consequently, more or less water ascends through the conduit II as the refuse descends into the refuse chamber. This upflow of water in-the conduit It not only tends to carry upward the grains of sand interspersed amongst the refuse-particles,-which is in itself an advantage but' is even vigorous enough to carry upward the smaller particles of the refuse where there is wide diversity in particle size. In this way acon'siderable part of the, smaller refuse particle under certain conditions, may not be discharged into refuse chamber 28 at all.

I have discovered a way of improving the operation of such systems by preventing or mitigating the sudden upflow of water from the chamber 20 through the conduit I8 (as above described) when the valve 21 is opened to discharge the separated heavy matter. This I accomplish 45 by permitting relatively easy outflow or escape of the water displaced from the chamber 20 by the incoming refuse,providing for this purpose a suitable avenue such as a conduit extending upward from said chamber 20. Of course the avenue thus provided for the outflow of water from the chamber 20 must offer a resistance to such outflow at least substantially equivalent to the hydrostatic head in the vessel 10, inorder to prevent objectionable discharge of water due merely to unbalanced excess of such head over such re sistance. Thus there will not be any objectionably vigorous upflow in the conduit It. It is not necessary, however, tocoinplicate the apparatus with an added pipe: on the contrary, I prefer to.

combine this function of water-outflow and discharge with that of air-venttng'the chamber 20 when it is being filled with water from the pipe 25, as already described. Or, to state the matter in other words, I maymake the pipe 21, already described, large enough for the required outflow of water, and may extend it only to such. height (above the liquid level in the vessel ll) as will permit the desiredoutfiow or discharge of "atanyratobe water through it under the impulse of the refuse descending into the chamber 20, while preferably precluding objectionable .discharge of' water due to the mere unbalanced hydrostatic head of the sand-and-water mixture in the vessel II. The discharge of water through the pipe 21 should ontrolled so late prevent sub-- above the liquid level extent of the conduit 21 .the conduit 21a may be ized to obtain maximum improvement with miniconduit 18, which may be as undesirable as an.

upflow. As the flow of water in the conduit 21 tends to carry some sand, which it is undesirable to lose, provision is preferably made for recovering it or re g it to the system. A simple way of doing this is to have the pipe 21 discharge into the vessel It as shown.

In the form of apparatus shown in Figs. I and II, the conduit 21 e nds toa substantial height in the vessel and makes a U-bend 30, and its return leg 3| opens and discharges into the lateral extension 11 ofsaid vessel, through an opening in its top or cover plate 32. An air vent opening 28 such as already mentioned may be provided at the crest of the U-bend 30. As here. shown, the U-bend 30 is a separate structure or piping assembly, movable up and down to vary and adjust the eflective height or above the liquid in the vessel Ill. To permit this, the legs of the U 30 telescope in suitably enlarged sections 33 of the conduit 21, with packing glands 34 to make air and liquid-tight joints: see Fig. III. By this adjustment, the effective height or crest and discharge capacity of the conduit 21 are controlled and varied, without materially affecting its air discharge capacity or its action as an air vent. Such adjustment may serve (inter alia) to take care of changes in the density or specific gravity of the separation liquid used in the vessel It, or of the volume of separated material to be discharged into chamber 20 each time, etc. Also, and possibly still more important, it permits of properly controlling and regulating the upflow in the conduit objectionable, while at the same time minimizing the discharge through the conduit 21 into the top of the vessel less or even beneficial) upflow in the conduit II can be insuredat all charging an objectionable amount of water into the top of the vessel Hi. In other words, the upflow in the conduit I84: and the discharge through balanced" or harmonmum disadvantage.

In the apparatus shown in Fig. IV, substantially similar results are obtained by a different mode of adjustment: 1. e., the legs of the U "a v are fixed and extend to the maximum desired height, with the air-vent opening 28a at the crest; and a number of valved by-pass connections 3! between the U legs are provided, at different levels. Obviously, the lowest'of these bypasses 25 that is-open determines the efi'ective height and the liquid-discharge capacity of the conduit 21a, without materially affecting its air discharge capacity.

Fig. 'V illustrates a simple form of construction in which the return leg 3lb of the conduit 21b consists of short removable interjointed sections 36. To the top of this returnleg ilb is connected an open vessel 31 whereto is also connected the rest of' the conduit 21b, which may be of flexible hose to permit the height of the vessel 31 to be adjusted and varied removing sections in the return by adding or leg 3 b,as suggested in dot-and-dash lines. The conduit 21b is shown as extending and opening in thevessei 31 substantially above its bottom, to facilitate venting of air at this point without interference from any liquid in said vessel. Means of-suspenl8, to an amount which will be untimes without ever dis I0. Thus a suitable gentle, harmsion for supporting the-vessel 31 are indicated by shall 88.

including therein a section or opening of fixed size, determined as correct (for given conditions of operation) by experience or by calculation, instead of a valve such as 40.

linF'igs. IV, V, and VI, various parts and tea-- tures are marked with the same reference characters as in Figs. 1411, with the sufiixes a, b, and 0, respectively, as a means of dispensing with repetitive description.

Having thus described my invention, I claim:

1. In the separation of materials of different specific gravities with the aid of a separating liquid in a vessel having a discharge conduit and refuse chamber, provided with shut-ofi' and discharge valves, for discharging separated heavier material from the lower portion of the vessel,

and also provided with means for supplying water to said refuse chamber between said valves preparatory to the passing of the separated heavy material through the first of saidvalves, the improvement which comprises permitting outflow of displaced water from said refuse chamber, against a resistance to such outflow at least substantially equivalent to the hydrostatic head in the vessel, and during the passage of said material into the chamber through the first valve, in such quantity as to obviate objectionable upflow of displaced water through said discharge conduit.

2. In the separation of materials of different specific gravities with the aid of a separating liquid in a vessel having a discharge conduit and refuse chamber, provided with shut-oil? and discharge valves, for discharging separated heavier material from the'lower vessel, and also provided with means for supplyseing water to said refuse chamber between said valves preparatory to the passing of the separated heavy material through the first of said valves, the improvement which comprises dis-\ returning displaced water from charging and 5 said refuse chamber into said vessel, during the passage of said material through the first valve, against a resistance to such outflow at least substantially equivalent to the the vessel, and in an amount so controlled as to permit no more than an -unobjectionable upflow of displaced water through said discharge conduit. I

3. In apparatus for separating materials of diflerent specific gravities with the aid of a cs separating liquid, the

rating vessel and means for supplying thereto the mingled materials to be separated, and for discharging the its upper portion; a discharge conduit and refuse chamber, provided with shut-oil and discharge valves, for discharging separated heavier material from the lower portion of said vessel; and means for supplying liquid to said refuse chamber; of a conduit extending upward from said 75 chamber permitting discharge of displaced liquid 210 has no air vent opening, but is portion of the hydrostatic head in combination with a sepaseparated lighter material from.

- means for supplying therefrom, when a batch of material is passed into the refuse chamber through said shut-oi! valve, in such quantity as to obviate objectionable upflow of displaced liquid through the first mentioned discharge conduit, and offering a resistance to such outflow at-leastsubstantially equivalent to the hydrostatic head in the vessel, for controlling suchoutflow of liquid as to prevent objectionable hydrostatic flow from the vessel through said conduit. I

. 4. In apparatus for separating materials of difierent specific gravities with the aid of a separating liquid, the combination with a senarating vessel and mean .for supp y g thereto the mingled materials to be separated, and for discharging the separated lighter material from its upper portion; a discharge conduit and refuse chamber, provided with shut-off and discharge valves, for discharging separated heavier material from the lower portion of saidvessel; and

liquid to said refuse chamber; of an outflow conduit. extending upward from said, chamber above the liquid level in said vessel, and providing for outflow of displaced liquid from said chamber, when a batch of material is passed into the refuse chamber through said shut-off valve, in such quantity as to prevent obiectionable upflow of displaced water through said discharge conduit, and including means for controlling and limiting such outflow to an amount sufllcient' for this purpose.

5. In apparatus for separating, materials of different specific gravities with the aid of a separating liquid, the combination with a separating vessel and means for supplying thereto the mingled materials to be separated, and for discharging the separated lighter material from its upper portion; a discharge conduit and refuse chamber, provided with shut-off and discharge valves, for discharging separated heavier material from the lower portion of said vessel; and means for supplying liquid to said refuse chamber; of a conduit extending upward from said chamber, permitting discharge of displaced liquid therefrom when a batch of material is passed into the chamber through said shut-off valve in such quantity as to obviate objectionable upflow of displaced liquid through the first mentioned discharge conduit, and offering a resistance to such outflow at least substantially equivalent to the hydrostatic head in the vessel; and means for varying and adjusting the liquid flow capacity of said conduit. g

6. In apparatus for separating materials of diflerent specific gravities with the aid of a separating liquid, the combination with a separating vessel and means for supplying thereto the mingled materials to be separated, and for discharging the separated lighter material from its upper portion; a discharge conduit and refuse chamber, provided with shut-oi! and discharge valves, for discharging separated heavier material from the lower portion of said vessel; and means for supplying liquid to said refuse chamber; of an outflow conduit extending upward from said chamber above the liquid level in said vessel, and discharging into the latter; and means for varying the effective height or crest of said outflow conduit above said liquid level, and the discharge of liquid therethrough.

7. In apparatus for separating materials of diflerent specific gravities with the aid of a seping the separated lighter material from its upper chamber above the liquid level in said vessel, and portion; a discharge conduit and refuse champroviding for the discharge of air'and of liquid I ber, provided with shut-oil and discharge valves, in such quantity as to obviate objectionable upfor discharging separated heaviermaterial-irom flow oi displaced liquid through the first menthe lower portion of said vessel: and meansror tioned discharge conduit; and means for varying 5 supplying liquid to said reiuse chamber; of an and adjusting the effective he ht or crest oi said outflow conduit extending upward from said outflow conduit above said liquid level, and thus chamber, providins againsta resistance to such regulating its liquid flow capacity substantially outflow at least substantially equivalent to the without aflecting the discharge of air therehydrostatlc head in the vessel, and for the disthrough.

charge of air from said chamber and also for the 9. In apparatus for separating materials 01' outflow of liquid in suehquantity as to obviate diii'erent specific gravitieswith the aid oi a sepobjectionable upilow oi displaced liquid through arating liquid, "the combination'wlth a separa said discharge conduit; and means for varying ing vessel andmeans for supplying thereto the and adjusting the liquidflow capacity of said mingled materials to be separated, and iordis- 15 conduit without aii'ecting. its air discharge charging the separated lighter material from its capacity. upper portion; adischarge conduit and refuse 8. In apparatus "forseparating materials of chamber, provided with shut-oil and discharge dlflerent specific gravities. with the aid or a sepvalves, for discharging separated heavier material arating liquid, the comb atlon with a separatfrom the lower portion of said vessel; and meanseo ingvessel and means ior-simplyingthereto the forsupplying liquid to said refuse chamber: 01' mingled materials to be separated, and for disa discharge conduit extending upward from said charging the separated lighter material from chamber to a crest above the liquid level in said,

its upper portion; adischarge conduit and refuse vessel, said conduit being or a capacity and exchamber, provided with shut-oi! and discharge tending to a height. which permit and limit 3 valves, for discharging separated heavier madischarge of liquid therethrough to an amount terial from the lower portion 01 said vessel: and sumcientto prevent objectionable upflow in the means for supplying'liquid to said refuse chain first mentioned dischargecondult. I ber; of a conduit extending upward from said l MARCUS A. WALKER. 

